/*                                           W3C Reference Library libwww Library Alert Class
                                     THE ALERT CLASS
                                             
 */
/*
**      (c) COPYRIGHT MIT 1995.
**      Please first read the full copyright statement in the file COPYRIGH.
*/
/*

   The Alert class defines a set of methods to be used by libwww to be used for passing
   prompts and message to a user. In order to maintain the Library core application
   independent and natural language independent, libwww does not know how to communicate
   with a _user_. Note here that a _user_ is a somewhat abstract notion for  something
   that can receive a message or prompt from the Library. This can for example be a
   person, but is may also be handled automatically by a robot or a client receiving a
   response from a HTTP server.
   
   Libwww has a set of _opcodes_ that classifies the nature of the message, for example
   that it is a question that must be confirmed in order to continue a request or simply a
   progress notification. The application can register a method for any number of the
   defined opcodes - in case the Library has a message for an opcode that does not have a
   method associated, the message is ignored. You can also globally disable any message
   send from the Library.
   
   _Note_: The library _core_ does not define any message or dialog methods - they are all
   considered part of the application. The library comes with a default set of methods
   which can be initiated using the function HTAlertInit()in HTInit module
   
   This module is implemented by HTAlert.c, and it is a part of the W3C Reference Library.
   
 */
#ifndef HTALERT_H
#define HTALERT_H

#include "HTReq.h"
/*

MESSAGE OPCODES AND MESSAGES

   The callback functions are defined as a generic callback where the caller can pass a
   set of input parameters and the callee can return a set of outptu parameters. Also note
   that all the *_PROG_*opcodes are a subset of HT_A_PROGRESS. This means that you easily
   can register a callback for allprogress reports.
   
 */
typedef enum _HTAlertOpcode {
    HT_PROG_DNS         = 0x1,          /* Doing DNS resolution */
    HT_PROG_CONNECT     = 0x2,          /* Connecting Active */
    HT_PROG_ACCEPT      = 0x4,          /* Connecting Passive */
    HT_PROG_READ        = 0x8,          /* Read data */
    HT_PROG_WRITE       = 0x10,         /* Write data */
    HT_PROG_DONE        = 0x20,         /* Request finished */
    HT_PROG_WAIT        = 0x40,         /* Wait for socket */
    HT_A_PROGRESS       = 0xFF,         /* Send a progress report - no reply */

    /* First word are reserved for progresss notifications */

    HT_A_MESSAGE        = 0x1<<8,       /* Send a message - no reply */
    HT_A_CONFIRM        = 0x2<<8,       /* Want YES or NO back */
    HT_A_PROMPT         = 0x4<<8,       /* Want full dialog */
    HT_A_SECRET         = 0x8<<8,       /* Secret dialog (e.g. password) */
    HT_A_USER_PW        = 0x10<<8       /* Atomic userid and password */
} HTAlertOpcode;

typedef struct _HTAlertPar HTAlertPar;

typedef BOOL HTAlertCallback   (HTRequest * request, HTAlertOpcode op,
                                int msgnum, const char * dfault, void * input,
                                HTAlertPar * reply);
/*

   If you don't expect any return values then replycan be NULL. The return value of the
   callback function can be used to indicate confirmation on a prompt (Yes or No).
   
  String Messages
  
   This is an enumerated list of messages that can be converted into a string table etc.
   
 */
typedef enum _HTAlertMsg {
    HT_MSG_NULL = -1,
    HT_MSG_UID = 0,
    HT_MSG_PROXY_UID,
    HT_MSG_FTP_UID,
    HT_MSG_PW,
    HT_MSG_FILENAME,
    HT_MSG_ACCOUNT,
    HT_MSG_METHOD,
    HT_MSG_MOVED,
    HT_MSG_RULES,
    HT_MSG_FILE_REPLACE,
    HT_MSG_RETRY_AUTHENTICATION,
    HT_MSG_RETRY_PROXY_AUTH,
    HT_MSG_REDO,
    HT_MSG_BIG_PUT,
    HT_MSG_SOURCE_MOVED,
    HT_MSG_DESTINATION_MOVED,
    HT_MSG_REDIRECTION,
    HT_MSG_ELEMENTS                         /* This MUST be the last element */
} HTAlertMsg;
/*

ENABLE OR DISABLE MESSAGES

   If you really don't want the library to prompt for anything at all then enable this
   constant. The default value is Interactive.
   
 */
extern void HTAlert_setInteractive      (BOOL interative);
extern BOOL HTAlert_interactive         (void);
/*

CREATION AND DELETION METHODS

   Message methods are registered in lists. By default a list is not enabled before you
   assign it as being _active_. This allows the application to maintain multiple lists of
   message handlers which can be swapped in and out as neeeded.
   
  Add a Callback Function
  
   Register a call back function that is to be called when generating messages, dialog,
   prompts, progress reports etc. The opcode signifies which call back function to call
   depending of the type of the message. Opcode can be any combination of the bitflags
   defined by HTAlertOpcode. If you register one callback for HT_A_PROGRESS then this will
   get called on all progress notifications.
   
 */
extern BOOL HTAlertCall_add (HTList * list, HTAlertCallback * cbf,
                             HTAlertOpcode opcode);
/*

  Delete a Callback function
  
   Unregister a call back function from a list
   
 */
extern BOOL HTAlertCall_delete (HTList * list, HTAlertCallback * cbf);
/*

  Delete a list of Callback Functions
  
   Unregisters all call back functions
   
 */
extern BOOL HTAlertCall_deleteAll (HTList * list);
/*

  Find a Callback Function
  
   Finds a callback function corresponding to the opcode. If none has been registered then
   NULL is returned.
   
 */
extern HTAlertCallback * HTAlertCall_find(HTList * list, HTAlertOpcode opcode);
/*

THE REPLY OBJECT

   The reply object is used for communicating input from the _user_ back to the Library.
   This is only required to use when for example the user is prompted for a file name etc.
   You can find several examples on how to use this in the default message and dialog
   module provided together with the Library.
   
 */
extern HTAlertPar * HTAlert_newReply    (void);
extern void HTAlert_deleteReply         (HTAlertPar * old);
/*

  Handle the Reply Message
  
   These methods provide the API for handling the reply message. There are two ways of
   assigning a message to the reply message - either by copying the buffer or by reusing
   the same buffer. In the latter case, the caller must make sure _not_ to free the reply
   message before it has been used.
   
 */
extern BOOL HTAlert_setReplyMessage     (HTAlertPar * me, const char *message);
extern BOOL HTAlert_assignReplyMessage  (HTAlertPar * me, char * message);
/*

   You can get the data back again by using this method:
   
 */
extern char * HTAlert_replyMessage      (HTAlertPar * me);
/*

 */
extern char * HTAlert_replySecret       (HTAlertPar * me);
extern BOOL HTAlert_setReplySecret      (HTAlertPar * me, const char * secret);

extern void * HTAlert_replyOutput       (HTAlertPar * me);
extern BOOL HTAlert_setReplyOutput      (HTAlertPar * me, void * output);
/*

ACTIVE SET OF CALLBACK FUNCTIONS

   A list can be assigned as being active in which case it is _visible_ for libwww. The
   Library does not know about inactive lists of methods.
   
 */
extern void HTAlert_setGlobal   (HTList * list);
extern HTList * HTAlert_global  (void);
/*

   You can also assign a callback directly to the global list. In this case you do not
   need to worry about creating the list - it will be created automatically.
   
 */
extern BOOL HTAlert_add         (HTAlertCallback * cbf, HTAlertOpcode opcode);
extern BOOL HTAlert_delete      (HTAlertCallback * cbf);
extern HTAlertCallback * HTAlert_find (HTAlertOpcode opcode);
/*

 */
#endif
/*

   
   ___________________________________
   
                           @(#) $Id: HTAlert.html,v 2.43 1996/08/08 16:40:53 frystyk Exp $
                                                                                          
    */
